The study will also assess a series of exploratory peripheral blood biomarkers, including, but not limited to, those delineated by DNA, RNA, protein, and/or metabolite alterations in an effort to more accurately predict those with, or at risk of having, the specific neurological disease. Finally, validation of the NIH Toolbox Odor Identification Test (NIHOIT) against the standard University of Pennsylvania Smell Identification Test (UPSIT) in patients with Parkinson's Disease will be analyzed.